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Black Toenail? Here’s What It Means and What You Should Do
A dark toenail isn’t always harmless—know when it’s time to seek medical care.
A black toenail can be alarming the first time you notice it. While it is often caused by a minor injury, discoloration beneath the nail can sometimes signal an infection or, in rare cases, a more serious medical condition. Understanding the possible causes and knowing which warning signs require medical attention can help you protect your foot health and avoid unnecessary complications.
The Most Common Cause: A Bruised Toenail
The leading cause of a black toenail is a subungual hematoma, which occurs when blood collects beneath the nail after an injury. This can happen if you accidentally drop a heavy object on your foot, stub your toe, or repeatedly place pressure on the nail while running, hiking, or wearing tight-fitting shoes.
As blood becomes trapped beneath the nail, the toenail gradually turns dark purple, brown, or black. Over time, the discoloration slowly moves toward the tip of the nail as it grows out.
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